Premium
Effects of acceleration, jerk, and field inhomogeneities on vessel positions in magnetic resonance angiography
Author(s) -
Stefansic James D.,
Paschal Cynthia B.
Publication year - 1998
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910400212
Subject(s) - acceleration , jerk , physics , position (finance) , nuclear magnetic resonance , magnetic resonance angiography , phase (matter) , compensation (psychology) , blood flow , magnetic resonance imaging , radiology , medicine , classical mechanics , psychology , finance , quantum mechanics , psychoanalysis , economics
Blood flow and magnetic field inhomogeneities lead to distortions in MR angiography (MRA) images that present added risk for stereotactic neurosurgical applications. These effects are demonstrated in an MRA image of a model of cerebrovas‐culature. Analysis of the effects of velocity, acceleration, jerk, and field inhomogeneities on vessel position is presented; results are used to predict vessel shifts for several cerebral blood vessels. The actual encoded position for flowing spins is shown to be a moment‐weighted average position. Maximum shift of 3.11 mm was reduced to 0.05 mm when velocity compensation was added. Velocity compensation applied specifically in the phase‐encoding direction reduces flow‐dependent shifts to the point that they can be safely ignored even if acceleration and jerk are present. Those prescribing and using MRA images for stereotactic applications must be aware of whether compensation is actually applied along the phase‐encoding axis when a flow‐compensated sequence is used.